This invention relates to an improved means and method for connecting valves to adjacent conduits, and more particularly to such improved means and methods utilizing a separate bolting ring threaded onto an end hub of the valve for connecting the valve to the conduit.
Heretofore, such as illustrated in FIG. 1A herein, a separate bolting ring has been utilized for connecting an end hub of a valve to a flow line or conduit. However, with such an arrangement, it has been difficult to obtain precise and accurate positioning of the ring onto the hub. Further, upon relative high torques exerted by high or excessive bolting forces against the bolting ring, the thread area adjacent the flow line is placed under an undesirable compressive loading.
One possible solution to the precise positioning of a bolting ring on the externally threaded hub has involved the use of interference threads on the hub and bolting ring. However, this has tended to be unsatisfactory as it is difficult to install a bolting ring with an interference thread, and if the bolting ring is heated and then inaccurately positioned on the hub, the ring is fixed at that location unless removed by difficult procedures.
Also, if the threaded connection is slightly loose after heating of the bolting ring, and subsequent cooling, the bolting ring may rotationally deform under subsequent excessive bolting torques.